For me it looks like the legs are moving the same! But what happens, is that the robotdog tilts. Thats why the front legs are farther from the ground. The back legs do not really leave the ground at all. Lifting two legs at the same time results in an unstable position thus resulting in the tiliting movement.
There are two ways to resolve that issue:
- Implement dynamic walking. This is when the legs move so fast that the model can't tilt as fast and the robotdog can balance on two legs for a short period of time (very simplified). This is very hard to do right! Just moving the legs faster could work but is normally not dynamic walking.
- Implement better static waking. This is when the robot has always 3 contact points with the ground, and the center of mass is in the middle of them. This is easier but still no trivial task. You would most likely also need to change your shoulder joints to be able to move the center of mass to the desired position. I recommend checking out this and the following videos from James Bruton on Youtube regarding this topic: https://youtu.be/TmY8CwuATiU
